More trees equal less carbon

I think most scientists would agree. The question is how much less. Scientists in Switzerland think that the earth could support nearly 2.5 billion additional acres of forest without shrinking our cities and farms. The mature trees would store 200 gigatons of carbon, whatever a gigaton is. But they also assert that this would store two-thirds of the carbon generated by industrial activity over the last 150 years. Other scientists dispute these numbers but do agree that more trees should be part of our battle against climate change.

The major planters of these trees would be Russia (with 373 million acres of forest); the U.S. with 255 million acres and Canada with 193 million acres.